Cartridge support added

Check for cartridge, identify if it's RAM or FLASH, and allow for erasing/programming the flash chip.

src/Makefile

@@ -2,7 +2,7 @@
 DEBUGGER=../module/Calypsi-remote-debug/src
 
 UNIT := F256K
-MEMORY := ROM
+MEMORY := RAM
 
 # Define OS-dependent variables
 
@@ -51,7 +51,7 @@ else ifeq ($(UNIT),F256)
 else ifeq ($(UNIT),F256K)
 	CPU=w65816
 	C_SRCS_DEBUGGER=$(DEBUGGER)/agent.c $(DEBUGGER)/c256-uart.c $(DEBUGGER)/low_level_WDC65816.s
-	SRCS_FOR_UNIT=C256/jumptable.s C256/io_stubs.c C256/extras.s C256/iecll.s C256/interrupts.s C256/f256-cstartup.s 
+	SRCS_FOR_UNIT=cartridge.c C256/jumptable.s C256/io_stubs.c C256/extras.s C256/iecll.s C256/interrupts.s C256/f256-cstartup.s 
 	CFLAGS_FOR_UNIT=-DMODEL=17 -DCPU=255 --code-model large --data-model large
 
 	ifeq ($(MEMORY),ROM)

src/cartridge.c

@@ -0,0 +1,129 @@
+/**
+ * @file cartdridge.c
+ * @author your name (you@domain.com)
+ * @brief Support for the flash cartridge
+ * @version 0.1
+ * @date 2024-08-11
+ * 
+ * @copyright Copyright (c) 2024
+ * 
+ */
+
+#include <stdbool.h>
+
+#include "cartridge.h"
+#include "timers.h"
+
+volatile uint8_t * cartridge = ((volatile uint8_t *)0xf40000);
+
+static short cart_id_memo = CART_ID_UNDEF;
+
+static bool cart_rw_match(uint8_t value) {
+	*cartridge = value;
+	uint8_t new_value = *cartridge;
+	return (new_value == value);
+}
+
+/**
+ * @brief Send a command to the flash chip
+ * 
+ * @param command the number of the command
+ */
+static void cart_flash_command(uint8_t command) {
+	cartridge[0x5555] = 0xaa;
+	cartridge[0x2aaa] = 0x55;
+	cartridge[0x5555] = command;
+}
+
+/**
+ * @brief Send the command to enter system ID mode on the flash chip
+ * 
+ */
+static void cart_flash_system_id_enter() {
+	// Attempt to enter software ID mode on the flash cartridge
+	cart_flash_command(0x90);
+}
+
+/**
+ * @brief Send the command to exit the system ID mode on the flash chip
+ * 
+ */
+static void cart_flash_system_id_exit() {
+	// Attempt to exit software ID mode on the flash cartridge
+	cart_flash_command(0xf0);
+}
+
+/**
+ * @brief Return a code describing the cartridge
+ * 
+ * @return short the code describing the cartridge (-1 for none found)
+ */
+short cart_id() {
+	if (cart_id_memo == CART_ID_UNDEF) {
+		// Start off assuming we don't have anything in the slot
+		cart_id_memo = -1;
+
+		// Check to see if there is RAM at the first byte of the cartridge
+		if (cart_rw_match(0x12) && cart_rw_match(0x23) && cart_rw_match(0x34)) {
+			cart_id_memo = CART_ID_RAM;
+		} else {
+			// Check to see if we have a flash chip
+			cart_flash_system_id_enter();
+
+			// Check for the manufacturer's ID we expect (BF for Microchip)
+			if (cartridge[0x0000] == 0xbf) {
+				// Yes... get the chip ID
+				uint8_t chip_id = cartridge[0x0001];
+				if ((chip_id == 0xd5) || (chip_id == 0xd6) || (chip_id == 0xd7)) {
+					cart_id_memo = CART_ID_FLASH;
+				}
+			}
+
+			// Leave system ID mode, regardless
+			cart_flash_system_id_exit();
+		}
+	}
+
+	return cart_id_memo;
+}
+
+/**
+ * @brief Erase the entire flash memory 
+ * 
+ */
+void cart_erase() {
+	if (cart_id() == CART_ID_FLASH) {
+		cart_flash_command(0x80);
+		cart_flash_command(0x10);
+
+		// Wait half a second
+		long target_jiffies = timers_jiffies() + 30;
+		while (timers_jiffies() < target_jiffies) ;
+	}
+}
+
+/**
+ * @brief Write a byte to the flash memory
+ * 
+ * @param address the address to write to (in CPU address space)
+ * @param value the byte to write to the address
+ */
+void cart_write(uint32_t address, uint8_t value) {
+	uint32_t cart_base_address = (uint32_t)cartridge;
+	uint32_t cart_end_address = 0xf7ffff;
+	uint8_t current_value = 0;
+
+	if (cart_id() == CART_ID_FLASH) {
+		if ((cart_base_address <= address) && (cart_end_address >= address)) {
+			cart_flash_command(0xa0);
+			
+			// Attempt to write the data
+			volatile uint8_t * dest = ((volatile uint8_t *)address);
+			*dest = value;
+
+			// Wait for the value to show up at the destination
+			long target_jiffies = timers_jiffies() + 5;
+			while (timers_jiffies() < target_jiffies) ;
+		}
+	}
+}

src/cartridge.h

@@ -0,0 +1,43 @@
+/**
+ * @file cartridge.h
+ * @author your name (you@domain.com)
+ * @brief Support for the flash cartridge
+ * @version 0.1
+ * @date 2024-08-11
+ * 
+ * @copyright Copyright (c) 2024
+ * 
+ */
+
+#ifndef __cartridge_h__
+#define __cartridge_h__
+
+#include <stdint.h>
+
+#define CART_ID_UNDEF	-2
+#define CART_ID_NONE	-1
+#define CART_ID_RAM		0
+#define CART_ID_FLASH	1
+
+/**
+ * @brief Return a code describing the cartridge
+ * 
+ * @return short the code describing the cartridge (-1 for none found)
+ */
+extern short cart_id();
+
+/**
+ * @brief Erase the entire flash memory 
+ * 
+ */
+extern void cart_erase();
+
+/**
+ * @brief Write a byte to the flash memory
+ * 
+ * @param address the address to write to (in CPU address space)
+ * @param value the byte to write to the address
+ */
+extern void cart_write(uint32_t address, uint8_t value);
+
+#endif

src/toolbox.c

@@ -34,6 +34,7 @@
 #include "dev/txt_c256.h"
 #include "dev/txt_evid.h"
 #elif MODEL == MODEL_FOENIX_F256 || MODEL == MODEL_FOENIX_F256K || MODEL == MODEL_FOENIX_F256K2
+#include "cartridge.h"
 #include "dev/txt_f256.h"
 #include "dev/kbd_f256.h"
 #include "dev/sdc_f256.h"
@@ -481,6 +482,42 @@ int main(int argc, char * argv[]) {
 	test_sysinfo();
 
 	printf("Foenix Toolbox v%d.%04d.%04d\n", VER_MAJOR, VER_MINOR, VER_BUILD);
+
+	const char * test_data = "Hello, world!";
+
+	volatile uint8_t * cartridge = ((volatile uint8_t *)0xf40000);
+
+	short cartridge_id = cart_id();
+	switch(cartridge_id) {
+		case CART_ID_NONE:
+			printf("No cartridge detected.\n");
+			break;
+
+		case CART_ID_RAM:
+			printf("RAM cartridge detected.\n");
+			break;
+
+		case CART_ID_FLASH:
+			printf("FLASH cartridge detected.\n");
+			// printf("Attempting to erase the flash cartridge.\n");
+			// cart_erase();
+			// printf("Attempting to program the flash cartridge.\n");
+			// for (int i = 0; i < strlen(test_data); i++) {
+			// 	cart_write(0xf40000 + i, test_data[i]);
+			// }
+
+			// for (int j = 0; j < strlen(test_data); j++) {
+			// 	txt_put(0, cartridge[j]);
+			// }
+
+			// printf("\n");
+			break;
+
+		default:
+			printf("Unable to determine whether a cartridge is present.\n");
+			break;
+	}
+
 	test_kbd();
 
 	// printf("Initializing IEC\n");